Funny you mention Turtles in Time, a game that locks you out of the ending if you play on easy.
This was with most game sback in the day. You could never get the true ending unless you played on hard. I remember a game called d-force for the snes. If you played on easy mode, you couldn't go past the 3rd level. Maybe it was th second, I dont remember to well. But yeah that's how games did ya back then.
Edit: some game slide super ghouls and ghost made you not only beat it on hand but also beat the game twice, to get the true ending.
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